Prevalence and determinants of full immunization among children under five in sub-Saharan Africa: A systematic review and meta-analysis (2013–2025)

Background: Despite global progress in childhood immunization, Sub-Saharan Africa (SSA) continues to report suboptimal coverage and high under-five mortality. This systematic review and meta-analysis assessed the prevalence and determinants of full immunization among children under five in SSA between 2013 and 2025. Methods: We systematically searched six electronic databases for studies published between January 2013 and May 2025 that reported the prevalence and/or determinants of full immunization in SSA. Eligible studies were original, peer-reviewed quantitative research. Data were analysed using random-effects meta-analysis, with subgroup and sensitivity analyses conducted to explore heterogeneity. Determinants were synthesised using pooled odds ratios (ORs) where applicable. Results: Thirty-one studies comprising 299,898 children were included. The pooled prevalence of full immunization was 51% (95% CI: 45%–58%), with substantial heterogeneity (I² = 100%). Prevalence varied widely across studies from 6% to 96%. Subgroup analyses revealed lower coverage in recent years and in studies with larger sample sizes. Key positive determinants of full immunization included maternal education (OR = 2.70), paternal education (OR = 2.48), antenatal care attendance (OR = 0.23 for non-attendance), institutional delivery (OR = 2.99), and household wealth (OR = 2.45). Children in rural areas (OR = 0.55) and those with mothers of higher parity (OR = 0.67) were less likely to be fully immunised. Conclusion: Full immunization coverage in SSA remains well below global targets, with wide disparities by country, socioeconomic status, and maternal healthcare utilization. Strengthening maternal health services, improving education, and addressing health system barriers are critical to improving coverage and reducing preventable child deaths in the region.